It said the pilots' union, BALPA, was launching industrial action over a pay dispute. British Airways had offered an 11.5 per cent pay increase over three years to BALPA, a deal already accepted by unions Unite and GMB, the airline said.

"Our customer teams – supported by additional colleagues - have been working tirelessly to help as many of you as possible and to provide options, including a full refund or re-booking to a different date of travel or alternative airline," said the statement.

"We continue to be available for constructive talks with BALPA, on the basis that there are no pre-conditions to those talks.

"If you have a flight booked with us on those dates, it is likely that you will not be able to travel as planned due to BALPA’s strike action. We are offering all affected customers full refunds or the option to re-book to another date of travel or alternative airline.

"Flights on BA CityFlyer, SUN-AIR and Comair are not affected."

The airline said it was working with other airlines to schedule larger aircraft to take the maximum number of passengers.

It warned any travellers whose flight had been cancelled tomorrow or on September 10 not to go to the airport, but to seek a refund.